Image formation through walls using a distributed radar sensor array

Through the wall surveillance is a difficult but important problem for both law enforcement and military personnel. Getting information on both the internal features of a structure and the location of people inside improves the operational effectiveness in search and rescue, hostage, and barricade situations. However, the electromagnetic properties of walls constrain the choices available as sensor candidates. We have demonstrated that a high range resolution radar operating between 450 MHz and 2 GHz can be used with a fixed linear array of antennas to produce images and detect motion through both interior and exterior walls. While the experimental results are good, it has been shown that the linear array causes signal processing artifacts that appear as ghosts in the resultant images. By moving toward a sensor concept where the antennas in the array are randomly spaced, the effect of ghost images can be reduced and operational and performance benefits gained.